U.S. Severe Weather Forecast (Coup d'œil sur la convection)

Day Three

acus01 kwns 010047 
Storm Prediction Center ac 010046 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0646 PM CST Monday Nov 30 2015 

Valid 010100z - 011200z 

..no severe thunderstorm areas forecast... 

occasional but generally isolated lightning strikes may persist 
through at least middle evening from northeast Texas into the lower 
Mississippi Valley and a portion of the Tennessee Valley this 
evening and possibly into the overnight. 

..nern Texas through the lower MS valley and Tennessee Valley... 

Scattered convection persists from northestern Texas through the Tennessee Valley. A 
few lightning strikes continue to be observed from northeast Texas into 
northern la and southern Arkansas. Activity is developing within expansive zone of 
isentropic ascent along a southwesterly low level jet that will gradually shift eastward 
tonight. The 00z radiosonde observations from Shreveport and Little Rock indicate 
700-500 mb lapse rates up to 7 c/km that are contributing to 150-300 
j/kg MUCAPE above the stable layer. This environment will continue 
to support the potential for lightning activity with the developing 
shallow but elevated convection. Slightly greater coverage of 
lightning should persist within the convective cluster over the 
lower MS valley region with more isolated activity farther NE into 
the Tennessee Valley where instability and lapse rates are weaker. 

.Dial.. 12/01/2015 


Mesoscale Discussion

acus11 kwns 301803 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 301803 

Mesoscale discussion 2003 
National Weather Service Storm Prediction Center Norman OK 
1203 PM CST Monday Nov 30 2015 

Areas affected...eastern South Dakota...SW-scntrl Minnesota...northwest Iowa...far NE Nebraska 

Concerning...heavy snow 

Valid 301803z - 010000z 

Summary...heavy snow will likely continue to develop across parts of 
eastern South Dakota...SW Minnesota...NE Nebraska and northwest Iowa over the next 3 to 6 hours. Snowfall 
rates are expected to increase to 1 inch per hour across parts of 
the mesoscale discussion area early this afternoon. 

Discussion...the latest surface analysis shows a 1015 mb low in far northwest 
MO. To the north of the surface low...winds are backed to the east 
across much of northwest Iowa...SW Minnesota...NE Nebraska and eastern South Dakota where surface temperatures are 
generally at or below freezing. Winter precipitation is ongoing 
across much of this area with heavy snowfall already being reported 
at Sioux Falls South Dakota. Mesoscale analysis currently shows an upper-level 
low over central Nebraska with a 75 to 90 knots middle-level jet in the southern and 
Central Plains. The exit region of the middle-level jet will overspread 
the mesoscale discussion area this afternoon enhancing synoptic-scale lift. In 
addition...forecast soundings across eastern South Dakota and SW Minnesota early this 
afternoon show an isothermal layer from 825 to 650 mb suggesting 
that conditions will be favorable for ice Crystal aggregation which 
will enhance snowfall rates. These factors combined with isentropic 
lift will support the development of heavy snow early this 
afternoon. Areas of heavy snowfall are expected to continue across 
southern parts of the mesoscale discussion area and gradually spread northward into NE South Dakota and SW 
Minnesota over the next several hours. Snowfall rates should reach up to 1 
inch per hour within the heaviest bands. 

.Broyles/Hart/Rogers.. 11/30/2015 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 42119513 41869646 42709737 43789833 44599956 45579908 
45859669 45349453 44139382 42119513